Add some debugging

exe/referator

@@ -12,7 +12,7 @@ $stdout.sync = true
 
 def parse_command(line)
   line = String(line).chomp
-  command = line[0...line.index(' ')].freeze
+  command = line[0...line.index(' ')].upcase.freeze
   rest = line[command.length..].strip.freeze
   [command, rest].freeze
 end
@@ -31,6 +31,7 @@ workdir = File.expand_path(workdir).freeze
 
 config = Referator::Config.new workdir
 footnotes = Referator::Footnotes.new config
+stacktrace = nil
 
 while (line = $stdin.gets)
   begin
@@ -39,6 +40,11 @@ while (line = $stdin.gets)
     when 'EXIT'
       success
       exit
+    when 'PING'
+      success :pong
+    when 'STACKTRACE'
+      success stacktrace
+      stacktrace = nil
     when 'REGISTER_FORMAT'
       data = JSON.parse rest
       config.formats.register(
@@ -76,6 +82,7 @@ while (line = $stdin.gets)
       raise 'Invalid command'
     end
   rescue => e
+    stacktrace = e.backtrace.map(&:freeze).freeze
     failure e.detailed_message
   end
 end